Recently, former White House adviser Anthony Scaramucci declared that President Trump is a “blue-collar president” — which some observers find curious, given his wealthy upbringing and boasts about being a billionaire. And in Sweden’s general election in September, the far-right Sweden Democrats finished in third place with 18 percent of the vote, while the center-left Social Democrats had their worst electoral performance in more than a century.

Why? My research in Hungary and Poland suggests that the right-wing populism’s rise and center-left parties’ decline result from the same process: blue-collar supporters shifting away from the left to embrace the populist right.